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标题：Dramatic declines in snowpack in the western US
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作者：Philip W. Mote ; Sihan Li ; Dennis P. Lettenmaier 等
期刊名称：npj Climate and Atmospheric Science
电子版ISSN：2397-3722
出版年度：2018
卷号：1
期号：1
页码：1-6
DOI：10.1038/s41612-018-0012-1
出版社：Nature Publishing Group
摘要：Mountain snowpack stores a significant quantity of water in the western US; accumulating during the wet season and melting during the dry summers and supplying much of the water used for irrigated agriculture; and municipal and industrial uses. Updating our earlier work published in 2005; we find that with 14 additional years of data; over 90% of snow monitoring sites with long records across the western US now show declines; of which 33% are significant (vs. 5% expected by chance) and 2% are significant and positive (vs. 5% expected by chance). Declining trends are observed across all months; states; and climates; but are largest in spring; in the Pacific states; and in locations with mild winter climate. We corroborate and extend these observations using a gridded hydrology model; which also allows a robust estimate of total western snowpack and its decline. We find a large increase in the fraction of locations that posted decreasing trends; and averaged across the western US; the decline in average April 1 snow water equivalent since mid-century is roughly 15–30% or 25–50 km3; comparable in volume to the West’s largest man-made reservoir; Lake Mead.